Ajax请求对象构造函数

Posted 2021-02-27

// ----------------------------------------
// Wrapper function for constructing a request object.
//	Parameters:
//		reqType: The HTTP request type, such as GET or POST.
//		url: The URL of the server program.
//		asynch: Whether to send the request asynchronously or not.
// ----------------------------------------
 
function httpRequest(reqType,url,asynch) {
 
	// Mozilla-based browsers
	if (window.XMLHttpRequest) {
		request = new XMLHttpRequest();
	} else if (window.ActiveXObject) {
		request = new ActiveXObject("Msxml2.XMLHTTP");
		if (!request) {
			request = new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
 
	// Request could still be null if neither ActiveXObject
	//   initialization succeeded
	if (request) {
		initReq(reqType,url,asynch);
	} else {
		alert("Your browser does not permit the use of all " +
			"of this application's features!");
	}
 
}
 
// ----------------------------------------
// Initialize a request object that is already constructed
// ----------------------------------------
 
function initReq(reqType,url,asynch) {
	// Specify the function that will handle the HTTP response
	request.onreadystatechange = handleResponse;
	request.open(reqType,url,bool);
	request.send(null);
}